chore : Deprecating FeatureToggles.IsEnabled (#113062)

* Deprecating features.IsEnabled

* add one more nolint

* add one more nolint

* Give better hints to devs in the deprecation message of IsEnabledGlobally

* adding more doc strings

* fix linter after rebase

* Extend deprecation message

pkg/services/navtree/navtreeimpl/admin.go

@@ -44,6 +44,7 @@ func (s *ServiceImpl) getAdminNode(c *contextmodel.ReqContext) (*navtree.NavLink
 			Text: "Organizations", SubTitle: "Isolated instances of Grafana running on the same server", Id: "global-orgs", Url: s.cfg.AppSubURL + "/admin/orgs", Icon: "building",
 		})
 	}
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if hasAccess(cloudmigration.MigrationAssistantAccess) && s.features.IsEnabled(ctx, featuremgmt.FlagOnPremToCloudMigrations) {
 		generalNodeLinks = append(generalNodeLinks, &navtree.NavLink{
 			Text:     "Migrate to Grafana Cloud",
@@ -99,6 +100,7 @@ func (s *ServiceImpl) getAdminNode(c *contextmodel.ReqContext) (*navtree.NavLink
 		})
 	}
 
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if (s.cfg.Env == setting.Dev) || s.features.IsEnabled(ctx, featuremgmt.FlagEnableExtensionsAdminPage) && hasAccess(pluginaccesscontrol.AdminAccessEvaluator) {
 		pluginsNodeLinks = append(pluginsNodeLinks, &navtree.NavLink{
 			Text:     "Extensions",
@@ -147,6 +149,7 @@ func (s *ServiceImpl) getAdminNode(c *contextmodel.ReqContext) (*navtree.NavLink
 		})
 	}
 
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if s.license.FeatureEnabled("groupsync") &&
 		s.features.IsEnabled(ctx, featuremgmt.FlagGroupAttributeSync) &&
 		hasAccess(ac.EvalAny(